To calculate the lower bound of $a$ given by the formula:

$a = \frac{v - u}{t}$

with values:

• $v = 8.91$ (3 significant figures)
• $u = 5.82$ (3 significant figures)
• $t = 9$ (1 significant figure)

we need to determine the lower bound of $a$. Here's how we approach it:

1. Identify Lower Bounds for each variable:

   • Since $v = 8.91$, the lower bound of $v$ is $8.905$.
   • Since $u = 5.82$, the lower bound of $u$ is $5.815$.
   • Since $t = 9$ to 1 significant figure, the lower bound of $t$ is $8.5$ (since $t = 9$ could range from 8.5 to 9.5).

2. Calculate the Lower Bound of $a$: Use the lower bounds of $v$, $u$, and $t$:

   [ a_{\text{lower}} = \frac{(v_{\text{lower}} - u_{\text{upper}})}{t_{\text{upper}}} = \frac{8.